Calypso bulbosa (L.) Oakes

Calypso, fairy slipper

This monotypic genus is palearctic in distribution, and extends south to Arizona in the mountains of the western United States. The genus Calypso is named for the beautiful nymph in Homer's Odyssey who waylaid Ulysses on his return to Ithaca. The specific epithet bulbosa is the Latin meaning "bulbed," in reference to the small pseudobulb of this species.

Photos courtesy of Emmet Judziewicz
DESCRIPTION: Plant arising from a bulbous corm. Leaf ovate, solitary, basal, 2-6 cm long and 2-4.5 cm wide. The leaf arises in late summer and persists through winter, withering after the plant flowers. Flower solitary, pendent, terminating an 6-21 cm tall stem. Sepals lanceolate to lance-linear, 1-2 cm long and 2.5-5 mm wide, purplish-pink to purplish-white, rarely white. Petals similar to sepals, sepals and petals spreading above the labellum. Labellum saccate, oblong (often described as "slipper-shaped"), 1.5-2.5 cm long and 6-11 mm wide, with two small projections at the apex and an "apron" of tissue extending from the opening. Labellum whitish-pink, liberally streaked with madder purple, spotted with the same near the opening. The "apron" has a brush of yellow hairs near the opening to the labellum, and the projections of the labellum are often yellowish as well. The column is petaloid and overhangs the opening to the labellum.

I can think of no other orchid that could be confused with Calypso, although some may see resemblance to species of Cypripedium.

Almost entirely restricted to Thuja bogs in the northernmost parts of the state, where it grows on dry hummocks of organic material. It may also be found in dry Thuja-Pinus-Abies woods over limestone/dolomite along the Lake Michigan Lake Superior shores. It seems to need cool soils.

May 20-June 25.

Calypso is pollinated by a number of species of bumblebees (Mosquin 1970, Boyden 1982). Like several other orchids in Wisconsin, it has a deceptive pollination system. The bumblebees are deceived by the yellow bristles, but upon visiting the flower, find no nectar or pollen reward.

DISCUSSION: This species is very rare in Wisconsin, and appears to have declined since Fuller (1933). Indeed, throughout the southern part its eastern range, Calypso has been in decline for the last 30 years or so. Given the preference of this orchid for cool soils, some feel its decline is an early indicator of global warming.

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